Help with buzz / hum that's making me insane r

Is it a hum (ground loop issue), buzz, or hiss from your tweeters?

Some hiss from tweeters may be normal when you put your ear right up to the tweeter. Buzz or crackling is another story.

If you have any low voltage halogen lighting this will produce a slight buzzing
The hum is most likely the suggested ground loop and the way the electrical panel was grounded

There are a few things I would look for.
- Is there a light dimmer on the circuit or on a neighboring circuit? If so disconnect and see if problem stops.

- Are all your connections tight in the breaker box? They come loose with time and vibrate and cause noise. It was amazing the improvement I had after tightening all the screw terminals. (Eliminating hf microphonic vibration).

Do NOT bypass the ground with cheater plugs. This is a safety issue.

What you describe is normal.

If you have to be that close to hear it you do not have a problem.

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Thanks everyone for your responses.

Sonofnorway: the only interaction between my video and audio setup is I have the audio of cable going through the integrated with a humbuster rca pair. I disconnected the that rca pair and unplugged all the power of the video setup (plasma screen, brain, cable and dvd) from the wall and the hiss was still there. I didn't unplug the cable from the cable box, but there was no power going to any of the video gear and they weren't linked to audio setup with any ICs.

Nick778: thanks for the clarifying question. It's definitely a hiss that also has a very slight fizz to it, like a digital hiss. It's only on the dome tweeters of the Dali's; the ribbon tweeter and other drivers are dead silent.

Apachef1: On the same circuit I have my NAS for my media server, a Cable modem, a printer, a phone and two lamps, both non-halogen. All kitchen appliances (fridge etc) are on a different line. (I can't install dedicated lines, FWIW).

Hififile: No dimmers, but kitchen apps are on a neighboring circuit. It's a condo in 50-unit building. I don't think my breaker box has any screws to tighten--it's all just breakers w/switches, but I'll check.

Herman: The only problem is that this is a new thing I'm experiencing. The hiss may have been there all along and I'm just now noticing it, but the way it manifests itself in listening is that vocalists with higher-pitched voices, or violins, etc have a very, very subtle distortion. So, vocals that seem to me like they should be crystal clear in production (annie lenox, etc) have a very slight throatiness to them. In most cases this just sounds like texture to me, but sometimes sounds like distortion. Again, it's very subtle and it could be that all the upgrades have made my system more revealing and I'm hearing things I wasn't before that sound like slight distortion but are just texture; however, I'm perplexed and do want to get to the bottom of this. I notice this more on voices in the middle of the soundstage. All other frequencies sound frigging amazing, and not all treble sounds this way, so it could be psychosomatic, but I would like to figure out if there's an issue or I need to adjust to my system. Sure I'm not the first!